Conventionally, lithium ion cells are cylindrical in shape and are composed of winding structured electrodes. However, the winding technology has disadvantages that limit the size (capacity) and integrity of the cells as outlined below:                1. Electrode smoothness problem at a certain length: This problem becomes more serious when cell size is increased. If the electrode smoothness or the variation of the thickness can not be maintained at a certain level, the size of the wound electrodes will not be consistent and that leads to the failure in fitting into the battery can.        2. Electrode swelling problem: This limits the electrode design, processing method, and thus the yield.        3. Current collector positioning problem: Large wound cells with long electrodes need multiple current collector tabs for high power applications. Proper alignment of the tabs is always a problem for large cylindrical wound cells. Electrode thickness variation with a long electrode winding causes poor alignment of the tabs. Poor alignment makes welding of the current tabs to the cell top difficult and induces poor reliability of the cell.        4. Heat dissipation problem: This factor limits the final size of the cell owing to the difficulty of heat dissipation in a radial heat diffusion path. Nonetheless, owing to the requirement of a high C-rate for high power applications, the heat dissipation problem will affect the applicability of the cylindrical cells in high power applications. It may also cause serious safety problems.        
Although stacking structured cells have advantages over the disadvantages outlined above, the stacking precision and labor intensive nature of the stacking process make the stacking structured batteries expensive and difficult in maintaining high yield while the size (corresponding to the number of layers) is increased.
A conventional stacking structured cell is shown in FIG. 1(a). The current collectors of the cathodes and anodes are normally positioned at the top of the electrode with a separator being disposed between the electrodes (Please refer to FIG. 1(b)). The disadvantages of the cell structure shown in FIGS. 1(a) and 1(b) are outlined as follows:                1. The electrodes are single pieces. This leads to the difficulty in each stacking process, as precision control is necessary during each stacking process.        2. The current collecting tab on each single electrode is either punched out from the uncoated portion of the metal substrate foil or a separated metal strip is welded to the electrode. Either way adds complications and cost to the assembling process.        3. Difficulty is encountered when welding the multiple electrode tabs together and attaching them to the main negative and positive posts under the battery cap within the limited headspace. This difficulty becomes more severe when the number of stacking layers is increased. If one of the electrodes is not welded properly, or if one of the electrode's current collector part (i.e. the uncoated substrate such as copper or aluminum foil) is broken, the performance and reliability of the resultant cell will be affected drastically. Owing to this reason, the consistency of the stacked cell becomes unpredictable especially when a vibration test is conducted.        4. For electrodes of a large surface area, if the current collector on each electrode is made too small, it will give poor current distribution and make the resultant cell perform poorly owing to the high resistance originating from each electrode.        
In the present invention, the electrode stacking problems mentioned above can be solved with more advantages obtainable compared to the conventional stacking technologies.